| 摘要 |
<P>PROBLEM TO BE SOLVED: To accurately determine the alcohol concentration of a fuel used for an internal combustion engine without the need of an alcohol concentration sensor in an internal combustion engine comprising a port injection valve for injecting a fuel into an intake port and a direct injection valve for injecting a fuel into a cylinder. <P>SOLUTION: The injection ratio of the fuel injection amount from a port injection valve 38 and the fuel injection amount from a direct injection valve 70 is obtained. In the case the engine load is changed, the engine load change amount is obtained. Temporary fluctuation of the exhaust air-fuel ratio accompanying the engine load change is sensed so that the fluctuation peak amount is obtained. Then, the alcohol concentration of the fuel currently used by the engine is determined by applying the engine load change amount, the fluctuation peak value of the exhaust air-fuel ratio corresponding thereto, and the injection ratio in this case to a determination model for the fuel alcohol concentration. <P>COPYRIGHT: (C)2011,JPO&INPIT |
